I think he means Syria is technically still at war with Israel since 1948. So bombing is fair game. If they wanted that situation to end, they could have made some other arrangements. But they did not.

Anyway, seems to me that at least until the end of 2019 there will be no major turn of events in the Syrian civil war, or perhaps until the very end of that war.

Assad is slowly regaining the few tracts of land that remain under rebel control.
Iran is slowly arming Hezbollah in Lebanon via domestic production (i.e in Lebanon), and arming Iraqi and Afghan militias.
Israel is slowly driving Iranian troops away from its border via one sided attrition warfare.
Russia is slowly and very silently driving Iran out of the other half of Syria.

These processes are all ongoing, and progressing somewhat positively for all.

What treaty did Israel sign with Syria that allows Israel to bomb Syria without warning?

Sorry, not treaty. A law. International law permits warring parties to conduct military activities, including airstrikes, between them.

So under international law, because it is allied to Syria, Iran can bomb Israel at will from Syria under this war that exists since 1948? Or is this one of those rules that are really just a masquerade for a caste system among nations, where the rules that apply for the cool kids don't apply for the losers?

Syria and Israel are more or less in a perpetually state of war. Syria can't go around pointing fingers, they more or less occupied Lebanon and ran it like a vassal state. Currently they are allowing another State to conduct attacks on Israel from their soil. I get that the Syrian regime is not strong enough to rid itself of Iranian proxies even if it wanted to. I have zero sympathy for Assad, he has bungled every opportunity to improve his country's relationship with the world.

It's actually an interesting question, since official declarations of war as a legal foundation to warfare (per the Hague Convention, for example) have largely fallen out of use after WW II, where the UN Charter outlaws war as a means of international politics (though the 1928 Briand-Kellogg Pact did the same already). The 1948 declarations by Syria et al against Israel were in fact some of the exceptions. Iraq also did formally declare against Iran in 1980, but Iran never did against Israel.

Of course international law has adapted to the post-1945 change by coming to refer to a "state of armed conflict" rather than war. Such a state can exist undeclared, defined by the exchange of hostilities between the military forces of state actors; but even previously, legal judgement was not so much based upon formal declarations as the question of who was the aggressor. Legally, Iran could certainly join a party to an existing declared war/armed conflict as an ally and thus become a party itself, though in this case it would be the aggressor side. On the flip side, that would also allow open military action by Israel against Iran.

I'm sure you could also argue that between belliciose rhetoric, clandestine operations, terror attacks and supply/use of proxy forces a state of armed conflict already exists between Iran and Israel anyway, but in that grey area legal justifications become really arbitrary.

Right now the status quo sees the Israelis bombing targets in Syria with little retalation into Israel. Why the Syrians accept that state of affairs is because the Israelis are careful to keep the level of pain below a certain threshhold, a level that they could increase radically if desired. Why the Iranians put up with being attacked is the more interesting question. Probably they percieve conflict as being far too risky and that they're consolidating their gains in Syria even through the air raids.

Right now the status quo sees the Israelis bombing targets in Syria with little retalation into Israel. Why the Syrians accept that state of affairs is because the Israelis are careful to keep the level of pain below a certain threshhold, a level that they could increase radically if desired. Why the Iranians put up with being attacked is the more interesting question. Probably they percieve conflict as being far too risky and that they're consolidating their gains in Syria even through the air raids.

The war in Syria is not exactly popular in Iran. If Iranians start coming back in body bags ......

I think you're right that that's a factor too - the Syrian adventure really doesn't have much to do with actual Iranian regional interests, so large number of casualties would be unpopular. More a project for the Revolutionary Guard and other special interest groups, it would seem. OTOH, if the US were to attack Iran, it might be the case that restraint - public opinion - would go by the wayside.

The question is now one of whether Assad has learned anything from the events of the past 5 years. For all that he has done to make his nation unsympathetic to the powers that be, he seems to have a nasty habit of survival.

Right now the status quo sees the Israelis bombing targets in Syria with little retalation into Israel. Why the Syrians accept that state of affairs is because the Israelis are careful to keep the level of pain below a certain threshhold, a level that they could increase radically if desired. Why the Iranians put up with being attacked is the more interesting question. Probably they percieve conflict as being far too risky and that they're consolidating their gains in Syria even through the air raids.

The war in Syria is not exactly popular in Iran. If Iranians start coming back in body bags ......

I don't think the Iranian presence in Syria is necessarily welcomed either. I think Assad et al was glad to have the support and desperately needed the help in the darkest days, but I think their usefulness is at end. More over, Israel will hold any attacks out of Syria as being an attack from the government - making the Iranians somewhat of a liability. The IDF used to routinely do punitive raids into Jordan after PLO attacks until finally the PLO was permanently forced out by the King. I suspect Assad has to be concerned about a large scale rocket attack being launched from Syrian ground. I suspect he is absolutely fine with the Israelis pre-empting such an attack, at least for now. The Israelis for their part seem to keep the casualties low on the Iranian side, mostly because the attacks generally are against equipment storage.

What treaty did Israel sign with Syria that allows Israel to bomb Syria without warning?

Sorry, not treaty. A law. International law permits warring parties to conduct military activities, including airstrikes, between them.

So under international law, because it is allied to Syria, Iran can bomb Israel at will from Syria under this war that exists since 1948? Or is this one of those rules that are really just a masquerade for a caste system among nations, where the rules that apply for the cool kids don't apply for the losers?

If Iran was allied with Syria in 1948, and repeated the declaration of war, then yes. But it wasn't and hasn't.

Iran has not officially declared war on Israel, but has engaged in military action against Israel many times over the years.

Would it be fair to say that Israel-Syria relations have never been better in the 70 odd years of their existence? There may be an opportunity here for more than just an understanding based on shared interests of the moment between the 2.

If Assad was willing to expel Iran I'm sure Israel would love to cut him most any deal he wants short of NBC weapons. But that would require Assad to turn on two of his three biggest benefactors and he lacks the military power to do so if even he had the desire. He's completely bought and paid for by Iran and stuck right next to Hezbollah, with both running around his country basically unsupervised. That was the price he had to pay for their help and I don't see anyway he can get out of that deal now. But it does explain why the Syrians don't particularly seemed to be concerned with the Iranians getting bombed every couple weeks.

Nobu and Josh you're bringing up true info, but a bit too late.
In 2011, prior to the civil war and the various spillovers and incidents that dragged Israel into an airstrike campaign, the relations between Syria and Israel were at an all time high. And by that I mean there were no real open threats, no military actions, there was quiet.

Olmert was Israel's PM at the time. He offered Assad the Israeli part of the Golan, in exchange to a full withdrawal of Iranian forces, and IIRC the ending of relations military relations with Iran.

Assad refused. And if we look at it from a dictator's point of view, it makes sense. Israel's Golan is a very small piece of territory in the vast Syria. Basically meaningless to Syria and only meaningful to Israel.

Iran, on the other hand, was a good ally to them. It was willing to aid Syria in any conflict it would drag it into.

Today it makes no sense to Israel to offer this deal again. Assad would almost surely take it, because it would mean no more airstrikes, but that ship has sailed.
Israel's interest in getting Iranian forces removed from Syria is being fulfilled via airstrikes and raids.

If about a year or 2 ago you'd read healines like this on Israeli media:
"Iranian forces are now estimated at X along the border, rise from past estimated Y".

Then today the much more scarce headlines on the topic are:
"Iranian forces are still trying to move weapons through central Syria".

So the IDF has succeeded in removing Iran's military presence from the south via attrition, and is now trying to do the same in central Syria and Lebanon's border.

There will be no deal because Israel basically got what it wanted without a deal.

What treaty did Israel sign with Syria that allows Israel to bomb Syria without warning?

Sorry, not treaty. A law. International law permits warring parties to conduct military activities, including airstrikes, between them.

So under international law, because it is allied to Syria, Iran can bomb Israel at will from Syria under this war that exists since 1948? Or is this one of those rules that are really just a masquerade for a caste system among nations, where the rules that apply for the cool kids don't apply for the losers?

If Iran was allied with Syria in 1948, and repeated the declaration of war, then yes. But it wasn't and hasn't.

Iran has not officially declared war on Israel, but has engaged in military action against Israel many times over the years.

Well, whatever the legalities the status quo seems to be that Iran supplies missiles that get fired at Israel from bordering territories, and in exchange the Israelis target Iranian troops in Syria on occasion.

Just because a war was not formally cancelled does not mean that countries are considered by the international community to actually be in a state of war. North and South Korea, for example.

If Assad was willing to expel Iran I'm sure Israel would love to cut him most any deal he wants short of NBC weapons. But that would require Assad to turn on two of his three biggest benefactors and he lacks the military power to do so if even he had the desire. He's completely bought and paid for by Iran and stuck right next to Hezbollah, with both running around his country basically unsupervised. That was the price he had to pay for their help and I don't see anyway he can get out of that deal now. But it does explain why the Syrians don't particularly seemed to be concerned with the Iranians getting bombed every couple weeks.

Iran fought to maintain the Syrian regime in power while Israel didn't help Assad and would have been just as happy to see the rebels win. And Israel - not Iran - annexed the Golan Heights. I'm not sure Syrians would consider those as reasons why Israel is the better ally. In terms of the Syrians not being "concerned" with IAF attacks on their soil, that's because there is nothing they currently can do about it. The basics of Assad's strategy are that he leaves all problems that can be delayed to future resolution, and deals with the crisis one situation at a time. Currently Idlib.